Start with a bin, brown materials, and green materials

Making compost at home means layering two types of organic waste—brown materials (dry leaves, shredded paper, cardboard) and green materials (grass clippings, vegetable scraps, coffee grounds)—in a container where they break down into dark, crumbly soil. You do not need special equipment or chemicals. A straightforward pile on the ground works, though a bin keeps rodents out and speeds decomposition by holding heat better.

The basic process takes three to six months if you turn the pile regularly, or six to twelve months if you leave it alone. Temperature, moisture, and the size of your materials all affect speed. A pile that is too wet smells bad; one that is too dry barely decomposes. The goal is the texture and moisture of a wrung-out sponge.

Key Takeaways

  • Layer brown materials (leaves, paper) and green materials (food scraps, grass) in a 3-to-1 ratio by volume, starting with brown on the bottom.
  • Keep the pile as moist as a wrung-out sponge and turn it every one to two weeks if you want finished compost in three months, or skip turning and wait six to twelve months.
  • Never add meat, dairy, oils, or diseased plants; these attract pests or spread disease to your garden.
  • Finished compost is dark brown, crumbly, and smells earthy—not like rotting food—and you can use it when ready in garden beds or potted plants.

Choose a bin or build a pile

A compost bin can be as straightforward as a wooden pallet frame wired together, a plastic storage bin with holes drilled in the sides and bottom, or a purchased tumbler. The bin does not have to be fancy—its job is to contain the pile and keep it warm enough to decompose quickly. An open pile on bare ground also works and costs nothing, though it takes longer and may attract more pests.

If you use a bin, place it on soil or grass, not concrete, so worms and microbes can move in from below. Drill or punch holes in the sides and bottom for air flow and drainage. If you use a tumbler (a barrel that rotates on a stand), you can turn the entire pile at once instead of forking it by hand, which speeds decomposition to two to three months.

For an open pile, choose a spot that gets partial shade and is away from your house and neighbors' windows. Piles in full sun dry out faster; piles in deep shade decompose more slowly. A pile at least three feet by three feet by three feet holds heat better than a smaller one.

Layer brown and green materials in the right ratio

The carbon-to-nitrogen ratio that works best is roughly three parts brown to one part green by volume. Brown materials are high in carbon and decompose slowly; green materials are high in nitrogen and decompose quickly. Together, they feed the microbes that do the actual work.

Start with a layer of brown material four to six inches deep—shredded leaves, straw, or torn cardboard. Then add a layer of green material two inches deep—grass clippings, vegetable scraps, or coffee grounds. Repeat until your bin is full or your pile is as tall as you want it. If you add a shovelful of finished compost or garden soil between layers, you introduce microbes that speed decomposition, though it is not required.

Chop or shred materials before adding them. Small pieces have more surface area for microbes to work on, so they decompose faster. A pile made from whole leaves and whole vegetable scraps may take twice as long as one made from shredded leaves and chopped scraps.

Water and turn the pile to speed decomposition

Check the pile's moisture once a week by squeezing a handful. It should feel like a wrung-out sponge—damp but not dripping. If it is dry, spray it with a hose until water runs out the bottom. If it is soggy and smells like ammonia or rotten eggs, turn it and add more brown material to absorb moisture.

Turning the pile every one to two weeks mixes materials, introduces oxygen, and speeds decomposition to three to six months. Use a garden fork to pull material from the outside of the pile (which is cooler and less decomposed) toward the center, and material from the center toward the outside. If you have a tumbler, rotate it five to ten times per week instead.

If you do not want to turn the pile, leave it alone and wait. Decomposition will happen on its own in six to twelve months, though the outside edges will stay cooler and less broken down. You can harvest finished compost from the bottom while the top is still decomposing.

Know what to add and what to avoid

Safe to add: vegetable and fruit scraps, coffee grounds and tea bags, grass clippings, leaves, shredded paper and cardboard, straw, wood chips, sawdust (from untreated wood), crushed eggshells, and plant trimmings.

Never add: meat, fish, bones, dairy, oils or fats, diseased plants, weeds with seeds, pet waste, or glossy or colored paper. Meat and dairy attract rats and raccoons. Diseased plants spread fungal or bacterial problems to your garden. Weeds with mature seeds will sprout when you use the compost. Pet waste can harbor parasites harmful to humans.

Avoid adding large branches or thick woody stems unless you shred them first. They take years to break down and can make the finished compost lumpy. Citrus peels and onion skins are safe but decompose slowly, so chop them small.

Recognize finished compost and use it

Finished compost is dark brown or black, crumbly, and smells earthy—like soil after rain. You should not be able to recognize the original materials. If you still see leaves, scraps, or wood chips, the pile needs more time. Sift it through a quarter-inch screen to remove unfinished chunks, or just use it as is; the rough pieces will finish breaking down in the soil.

Use finished compost when ready. Mix it into garden beds at a depth of two to four inches before planting, or use it as a top dressing around existing plants. You can also use it to fill potted plants or blend it with store-bought potting soil. There is no risk of over-explore compost—it will not burn plants the way chemical fertilizer can.

Store finished compost in a bin or pile covered with a tarp to keep it from getting too wet. It will not decompose further once it is finished, so it can sit for months without losing quality.

Troubleshoot common problems

Pile smells like ammonia or rotten eggs: Too much green material or too much moisture. Turn the pile and add brown material (shredded leaves or cardboard). Reduce watering.

Pile is not heating up or decomposing: Too much brown material, not enough moisture, or materials are too large. Add more green material, water the pile, and chop materials smaller. Piles smaller than three feet by three feet feet also decompose slowly.

Flies or gnats around the pile: You have added meat, dairy, or oils, or the pile is too wet. Stop adding those materials, turn the pile, and add brown material. Bury food scraps under at least six inches of brown material so they are not exposed.

Rodents in or around the pile: You have added meat, dairy, or oily foods. Remove those materials and switch to a bin with a solid bottom and tight-fitting lid. Do not add any more animal products.

Frequently Asked Questions

How long does it really take to make compost?

Three to six months if you turn the pile every one to two weeks and keep it moist and well-mixed. Six to twelve months if you leave it alone. Temperature matters—piles decompose faster in warm weather and slower in winter. A small pile or one made from large, whole materials takes longer than a large pile made from chopped materials.

Can I compost in an apartment or small space?

Yes. Use a small plastic bin with a lid (12 to 18 inches on each side) kept indoors or on a balcony. Layer food scraps with shredded paper or cardboard, keep it moist, and turn it weekly. It will smell if you add meat or dairy, so stick to vegetable scraps, coffee grounds, and paper. Finished compost will be ready in two to three months.

What if I do not have brown materials?

Shredded newspaper, cardboard, or paper towels work well and are usually free. Sawdust from untreated wood, straw, or wood chips also work. If you have none of these, you can compost with mostly green materials, but the pile will be wetter and may smell bad. Add brown material as soon as you can.

Can I add diseased plants or weeds to compost?

Not safely. Fungal and bacterial diseases survive in home compost piles unless the pile reaches 140°F throughout, which is hard to maintain without a thermometer and regular turning. Weed seeds also survive. Throw diseased plants and mature weeds in the trash instead.

Do I need to buy compost starter or activator?

No. A shovelful of finished compost or garden soil introduces the microbes you need. If you do not have either, the microbes are already on the materials you add and in the soil beneath the pile. Decomposition will happen on its own, just more slowly. Commercial activators are not necessary.